Increased seat belt usage has reduced tragedies. Despite its social utility, seat belt usage does not cleanly fit into tort concepts. Before the seat belt laws, courts found that there was no duty to wear the safety restraint absent statutory mandate, a holding that was surely buoyed the relative non-use at the time. Hampton v. State Highway Com., 498 P.2d 236, 249 (Kan. 1972) (“One is not required to anticipate negligence and guard against damages which might ensue if such negligence should occur. So likewise the traveler has the right to assume the highway is reasonably safe for travel-as the jury here was instructed without objection. In short, there was no duty to use a seat belt, either under the common law standard of due care or to mitigate damages. That being so, the trial court did not err in excluding evidence of plaintiff's nonuse for it was not relevant to any issue to be determined.”) (internal citations omitted).

Even after the mandatory seat belt laws, any iteration of a “seat belt defense,” an umbrella term for seat belt non-use evidence to avoid or apportion liability and/or damages, has been (and remains) the source of much dispute. Tori R.A. Kricken, The Viability of the Seatbelt Defense in Wyoming - Implications of and Issues Surrounding Wyoming Statute 31-5-1402(F), 5 Wyo. L. Rev. 133, 134 (2005). Perhaps this will be less so moving forward as consciousness of safety risks increases (by way of ubiquitous national and state advertising) and seat belt usage rates continue to increase at a time where most states have some form of a comparative fault system.E.g., Nabors Well Servs. v. Romero, 456 S.W.3d 553, 555 (Tex. 2015) (“These changes have rendered our prohibition on seat-belt evidence an anachronism.”); see also, David G. Owen, Products Liability Law, § 17.5 (West 2005).

Crashworthiness cases make it difficult to exclude seat-belt non-use from consideration. Like the mandatory use seat belt laws, our conception of crashworthiness cases is of recent vintage; in fact, the opinion that established our modern conception of crashworthiness was issued the year after the creation of The National Highway Transportation Safety Administration. In 1968, the Eighth Circuit Court of Appeals held “[where the injuries or enhanced injuries are due to the manufacturer’s failure to use reasonable care to avoid subjecting the user of its products to an unreasonable risk of injury, general negligence principles should be applicable.” Larsen v. Gen. Motors Corp., 391 F.2d 495, 502 (8th Cir. 1968). Thus, a manufacturer was not absolved from a faulty design that caused or exacerbated injuries following a collision just because another person (or the plaintiff) caused the collision; its duty of reasonable design extended to accidents. Manufacturers are not insurers of safety and there is no obligation to create a crash-proof vehicle, but manufacturers must eliminate unreasonable risks by taking reasonable steps to reduce potential for injury in a crash. David G. Owen, Products Liability Law, § 17.3 (West 2005). To consider a vehicle’s crashworthiness, the factfinder must consider the design as a whole, which invariably includes the system of restraints. Consequently, a plaintiff’s failure to use a safety restraint seems likely to be relevant and should be admissible.

Yet, divergent state statutes complicate the issue. Some states categorically ban (e.g., S.C. Code Ann. § 56-5-6540(c)) or permit (Okla. Stat. tit. 47, § 12-420) seat belt non-usage as evidence in a civil case. Other states allow the evidence but only to mitigate damages (e.g., N.Y. Veh. & Traf. Law § 1229-c(8)) and, even then, some states only allow a reduction by a specified percentage e.g., Or. Rev. Stat. Ann. § 31.760 (limiting the reduction to 5%). Or the seat belt non-use is admissible to the issue of causation, but not comparative fault or contributory negligence, e.g., Tenn. Code Ann. § 55-9-604.

Applying these statutes as written leads to peculiar results, such as a plaintiff not being able to maintain a lawsuit for a defective seat belt because, to do so, she would need to raise seat belt evidence. Carlson v. Hyundai Motor Co., 164 F.3d 1160, 1162 (8th Cir. 1999) (applying Minnesota law). Note the Minnesota legislature has since changed the law, and that other courts did not reach the same result when considering the question. Minn. Stat. Ann. § 169.685(4)(b); Glyn-Jones v. Bridgestone/Firestone, Inc., 857 S.W.2d 640, 644 (Tex. App. 1993). Judge Posner provided an example of how such categorical bans, if read literally, can lead to absurd results. Considering North Carolina’s mandatory seat belt law that provided evidence of seat belt non-usage was inadmissible in all civil and criminal cases (except those enforcing the seat belt requirement), Posner illustrated a shortcoming of the literal reading: “So if an irate passenger ripped off his seat belt, tore it from its moorings, and used it to strangle the driver, in the ensuing murder trial the prosecution would be forbidden to identify the murder weapon because to do so would be to show that the defendant had not been wearing his seatbelt.” Barron v. Ford Motor Co. of Canada, Ltd., 965 F.2d 195, 198 (7th Cir. 1992).

Perhaps consequently, courts occasionally permit evidence of seat belt non-use in a crashworthiness case despite a categorical statutory ban of such evidence. MacDonald v. General Motors Corp., 784 F. Supp. 486, 499–501 (M.D. Tenn. 1992) (allowing seat belt non-use as evidence despite statute bar: “In no event shall failure to wear a safety belt be considered as contributory negligence, nor shall such failure to wear a safety belt be admissible as evidence in a trial of any civil action.”). Along this vein, other courts also have read the limited use statutes narrowly so as to protect a defendant manufacturer’s ability to defend against crashworthiness claims. Bayerische Motoren Werke Aktiengesellschaft v. Roth, 252 P.3d 649, 660 (Nev. 2011) (noting that seat belt non-use may be admissible in crashworthiness action despite statute barring such evidence for its use as negligence or causation in any civil action); GMC v. Wolhar, 686 A.2d 170, 176–77 (Del. 1996) (denying retroactive application). The essential crashworthiness inquiry is a thought exercise from a hypothetical baseline: how would plaintiff have fared in the crash without the alleged design defect? The seat belt issue is hard to excise from that inquiry because it will often explain how the plaintiff encountered the secondary safety features (i.e., an allegedly defective door latch). See e.g., Jimenez v. DaimlerChrysler Corp., 269 F.3d 439, 455 (4th Cir. 2001) (ordering new trial because trial court excluded seat belt non-use evidence that presented alternative explanation of the alleged injuries as Defendant should have only been responsible for those injuries sustained as a result of the allegedly defective door latch and not those injuries attributable to non-use of the seat belt had the van been equipped with a non-defective latch). The above-cited cases are pragmatic holdings that protect the manufacturer’s right to a fair trial. While such holdings are the norm, there are notable exceptions. See, e.g.,Gaudio v. Ford Motor Co., 976 A.2d 524, 538 (2009) (“In addition to its refusal to prohibit evidence of seat belt non-usage, the trial court should also have precluded evidence that the F-150 had a seat belt system and/or that the purpose of the seat belt system was to serve as the primary restraint system.”).

These holdings make it more likely that a finding of liability turns on a moral fault, which is a happy result. The tort system can be slow to react to societal changes, and the swift change in opinion and usage of seat belts strains the system. The cases—occasionally straining—to allow evidence of this commonplace consideration bolster the legitimacy of the trial system; the laws excluding seat belt non-usage create an elephant in the room for crashworthiness cases by preventing an answer to the jury’s first question.